The present disclosure is directed to temperature data acquisition in areas with complex geometric features. In particular, the present disclosure is directed to temperature data acquisition on process tubes in a furnace.
Generally, energy efficiency for industrial processes is becoming more important. For many processes, such as hydrogen production, the efficiency of the process is related to the ability to monitor/maintain certain temperatures. Measuring temperature in areas with complex geometric features can present several challenges. For example, when measuring temperatures at specific locations of the features, inconsistency in taking the measurements at the specific location on the feature can result in inconsistent measurements. More precise monitoring of the temperature at the specific location on the feature can permit improved energy efficiency by permitting more accurate data to be used for process control.
One area having complex geometric features is a furnace (including, but not limited to, a steam methane reformer). One type of furnace can utilize numerous process tubes (including one configuration that has more than 400 process tubes) containing a catalyst (for example, a reforming catalyst) for transporting a process fluid (for example, steam and a hydrocarbon). The furnace, in one example, can include vertically extending process tubes positioned in parallel rows with about 30 to 60 tubes in each row. The distance between two rows of tubes is about 2 to 3 meters. The tubes can extend vertically about 12 meters and have an outer diameter of 100 to 150 millimeters. The tubes can be positioned in the row with a center-to-center spacing of 250 to 500 mm. About 10 to 20 burners can be positioned between each set of two rows of tubes. A total of eight or more rows of tubes and nine or more rows of burners can be included in the furnace.
One way to improve the efficiency of a furnace is to maintain a uniformity of temperature among the process tubes at a predetermined elevation in the furnace. Thus, the measuring or monitoring of the temperature of each of the process tubes at a predetermined location or elevation can be needed to obtain the desired efficiency improvement. In addition, the process tubes of a furnace can be under very high internal pressures (up to about 50 atmospheres) and at very high temperatures (up to about 950° C.). Thus, a slight change in temperature can reduce the operational life of a process tube. For example, operating at about 10° C. above the design temperature for the tube can reduce the operational life of the tube by as much as one half. The cost of repairing and/or replacing the tubes can be high due to the use of special alloys in the tubes that are needed to permit the tubes to survive the operational conditions of the furnace. As such, furnace operators also measure/monitor the tube temperatures to avoid exceeding the tube design temperature in addition to trying to obtain efficiency improvements.
In one method of measuring/monitoring the temperature of process tubes, an operator may use an optical pyrometer. When using the optical pyrometer, the operator aims the device at a predetermined location on a process tube and then activates the device. Upon activation, the optical pyrometer measures thermal radiation and displays or records a corresponding temperature for the predetermined location on the process tube. The operator repeats the process for each of the tubes. The use of the optical pyrometer has several drawbacks in that high temperature exposure may occur, the same predetermined location may not be used for all tubes, the temperature of a selected tube may not be measured, the same tube may be inadvertently measured twice instead of the desired adjacent tube, and the process may take too long resulting in temperature fluctuations for the tubes.
Therefore, what is needed is to provide a method for measuring the temperature of complex geometric features using a standardized process that permits quicker data collection.